Index: /trunk/docs/index.txt
===================================================================
--- /trunk/docs/index.txt	(revision 592)
+++ /trunk/docs/index.txt	(revision 593)
@@ -19,4 +19,17 @@
     The entire documentation is also available as a single
     `PDF document <./ZOOProject.pdf>`__ |image|  and `ePub document <./ZOOProject.epub>`__
+
+License
+=======================
+
+The ZOO-Project documentation is released under the
+`Creative Commons Attribution-ShareAlike 4.0 International Public License <https://creativecommons.org/licenses/by-sa/4.0/legalcode>`__
+(CC-BY-SA). This license must be kept when editing or creating a new documentation file.
+
+.. image:: ../../_static/images/by-sa.png
+   :target: https://creativecommons.org/licenses/by-sa/4.0/legalcode/
+   :height: 31px
+   :width: 88px
+
 
 About ZOO Documentation